Women are not little men
Women are not simply smaller, lighter men - this realisation sounds like a truism, but does not yet seem to be widespread in sport and training theory. There are still very few sports medicine studies that focus exclusively on women. As a result, female athletes have been training for decades according to training plans that were designed for men.
The main difference between women and men is the menstrual cycle. The extent to which female hormones influence athletic performance has long been underestimated. But not Prof Dr Petra Platen. She is head of the Department of Sports Medicine and Sports Nutrition at Ruhr University Bochum and has been researching the topic for many years. Prof Platen knows that although the connection between the menstrual cycle and sport has been known in science for decades, there has never been a significant breakthrough in training practice. "I believe this is because this female topic is still taboo even in this millennium," says Platen. But the variability of the results is also a problem with such research. "You can see that from the fact that a cycle of between 23 and 35 days is considered normal."
What is a cycle?
However, something is increasingly changing: more and more female athletes are talking publicly about period problems or low performance due to cycle fluctuations and, as Platen also notes, are calling for the topic of the cycle to be normalised so that they can discuss it with their coaches.
Saba Shakalio also knows that there are gaps in the knowledge of coaches in particular. The sports scientist and physiotherapist, who works as an athletics trainer for FC St. Pauli's female footballers, is researching the influence of menstrual cycles on the training periodisation of competitive female athletes. "Most women in competitive sport are trained by men," she says, "and as an athlete, you first have to explain to some of them what a menstrual cycle actually is. A cycle is not a period, a period is not a cycle."
The female cycle refers to the number of days from the start of menstruation (or menstruation/period) until the next menstruation begins. Hormone fluctuations can occur not only during the menstrual phase, but throughout the entire cycle. Shakalio believes that lack of knowledge about this is one of the reasons why many female athletes do not communicate openly with their coaches. A survey conducted by Südwestrundfunk in 2021 among 719 top female athletes backs this up: more than half of the female athletes surveyed felt uncomfortable talking to coaches about menstruation. 40 per cent of all participants were also of the opinion that the menstrual cycle is not sufficiently taken into account during training and competitions.
A dilemma familiar to many female athletes
Former elite cyclist Lea Feder, who competed in cycling races until four years ago, is also familiar with the problem: "It was definitely not the order of the day for coaches to have knowledge about training with the female cycle, to discuss it and apply it in training." The now 32-year-old rode for Team Stuttgart in the national league and in international competitions for several years. The many years in competitive sport and lack of information had led to health problems for her.
After stopping the pill, she noticed that her period had stopped. As a competitive athlete, she couldn't do anything with her gynaecologist's advice to stop training and put on a little weight. "With a full racing calendar of around 800 training hours a year, you can't just say that you're going to train less and cancel all your races."
A dilemma that many ambitious sportswomen are familiar with. However, what many people don't realise is that although women who take the pill bleed every month, this is only a so-called withdrawal bleed and not a real period. This is a big problem for Feder. "Women who take the pill no longer have any biofeedback due to the lack of a period. They can no longer see from their own cycle whether they are doing well or not."
Hormonal imbalance
According to sports scientist Shakalio, a missed period (amenorrhoea) is always a sign that the body is under enormous stress. Untreated amenorrhoea has a negative effect on the entire female organism, especially on bone metabolism. If there is no period for a long time, the oestrogen level is also very low for a long time. As a result, the bones lose mass and osteoporosis can develop. "You can see this in female athletes because they have a higher risk of stress fractures," explains sports physician Petra Platen.
Amenorrhoea can also lead to a desire to have children remaining unfulfilled. Excessive physical exertion disrupts the hormone balance. As a result, the ovaries no longer release eggs, the period stops and the woman cannot become pregnant.
Many female athletes are unaware of the consequences of amenorrhoea. According to a survey of female athletes in the UK in early 2023, 36 per cent have ignored one or more missed periods. The athletes thought the menstrual irregularities were normal or even beneficial for their performance. Particularly worrying: 30 per cent of the women surveyed were told by their doctors that missing periods were "normal" given their level of activity. The doctors neither looked for the cause nor tried to remedy the amenorrhoea.
A missing period was not seen as a problem in Feder's cycling team either. "A missed period was a relief back then. It was practical because then we didn't have to worry about it," she reports. Not having a period was seen as a blessing for female cyclists. In fact, we now know that it's the exact opposite.
Back then, Lea Feder began to explore the topic on her own initiative and tried out the knowledge she had acquired on herself - her parallel medical degree helped her to do so. And because she knew that many women felt the same way as she did and that there was a lack of knowledge about the female cycle in sport, she founded Way to Win as her own coaching and performance diagnostics company in 2017. Together with a number of experts, she wanted to raise women's awareness of sustainable competitive sport.
Bio-doping through a healthy cycle
This is because women without a functioning cycle have to contend with another disadvantage in addition to the consequential damage: their bodies have fewer anabolic, i.e. anabolic hormones, which have a performance-enhancing effect. "I would tell a very performance-orientated woman that she should consider using a different contraceptive method," says Platen. Taking the pill leads to a reduction in the body's own production of oestrogen and progesterone. Together with testosterone, these hormones are crucial for building muscle. "The potential that women actually have due to the increase in the body's own hormone concentrations is eliminated by the pill," says the sports physician.
Her studies have shown that women are most trainable in terms of strength before and during ovulation; these different cycle effects could not be observed in endurance training. However, the professor is reluctant to generalise her findings, as there are still too few studies on the subject.
Luteal phase, higher risk of injury
Saba Shakalio also recently investigated the different performance of women over the course of a menstrual cycle in a study together with the Cologne Sports University. Over a period of several months, she measured the speed endurance of twelve female water polo players in the first national league - in three phases of the menstrual cycle: period, follicular phase (before ovulation) and luteal phase (after ovulation). The result: "The women were actually better before ovulation than after ovulation," says Shakalio.
Lea Feder has made similar observations. She likes to visualise the female cycle using the seasons model. The phase before ovulation is therefore spring and ovulation is summer: "Female athletes are very motivated and creative at this time, they can build up muscle mass and then regenerate very well." According to the future doctor, female racing cyclists should use this time specifically for strength training and interval units. This is because the hormone oestrogen in particular reaches peak levels at this time.
Then comes the stormy autumn (luteal phase) and the hormone situation changes significantly. After a brief high, first oestrogen and then progesterone drop to their lowest levels. The progesterone, which initially still rises after ovulation, contributes to the metabolism becoming catabolic, i.e. breaking down. It is more difficult to build muscle during this phase and intensive exercise is perceived as more strenuous. Female athletes are also at a higher risk of injury during the luteal phase. It prepares the female body for possible fertilisation and ligaments loosen.
Women who take the pill no longer have any bio-feedback due to the lack of periods. They can no longer see from their own cycle whether they are doing well or not. - Lea Feder, doctor and sports coach
Feder explains that the hormonal changes after ovulation require a lot of consistency and rest from the outside: "The more you create stress from the outside with intensive training or periods of hunger, the more the hormonal fluctuations are amplified. This can lead to premenstrual syndrome and period pains that slow you down in your next training session." By periods of hunger, Feder is referring to energy bottlenecks that are imposed on the body either permanently in the form of a calorie deficit or temporarily due to a lack of carbohydrates during training.
Nutrition adapted to the cycle
Helen Bauhaus, nutritionist at the Cologne Sport University, says that energy requirements also depend on the individual cycle phases. In the luteal phase, i.e. after ovulation, women have a resting energy expenditure of 200 to 300 kilocalories more compared to the follicular phase. Bauhaus therefore advises including a small snack between meals on these days: "A small porridge, a piece of low-fat cake such as banana or fruit bread and a shake with oatmeal and protein-rich milk are best for this."
Saba Shakalio is even of the opinion that female athletes also need a cycle-adapted nutrition plan due to their changed energy requirements. "We already know, for example, that women are less able to store sugar during the luteal phase. After intensive training, it is important to compensate for this with an adapted diet."
The topic of energy supply was also Lea Feder's way back to a regular cycle: "For a long time, I tried to put on weight with weight gainer shakes after every meal. That didn't help at all with the secondary amenorrhoea." The key point, as she says herself, was to increase her food intake during training. Instead of water, she fills her bike bottles with carbohydrate-rich drinks.
Cycle-based training does not mean that you train less or more, but that you adapt the training periodisation to your cycle. - Saba Shakalio, sports scientist and physiotherapist
The doctor was lucky. As she got her period back quickly by changing her diet, she was spared severe symptoms. Nutritionist Helen Bauhaus says that an adjusted carbohydrate intake is essential in order to establish a healthy cycle. "Otherwise, in addition to the absence of menstruation, other symptoms often occur on a physiological, metabolic, endocrinological and psychological level," says Bauhaus.
A healthy body is everything
But even with a healthy cycle, women can often suffer from pain, fatigue or exhaustion during their period. In Feder's seasonal model, menstruation therefore represents winter. In a BBC survey conducted in 2020, 60 per cent of 500 female athletes stated that their period had an impact on their athletic performance, even causing them to skip training or competitions.
But this is not always necessary. According to Shakalio and Feder, cycle-adapted training does not change the amount of training, but rather the type of training load. "Cycle-based training does not mean that you train less or more, but that you adapt the training periodisation to the cycle," says Shakalio. After all, you don't always train at the same intensity in competitive sport anyway. Feder explains: "Cycle-controlled training is primarily about how we can get more effect from the same training. You should utilise the individual cycle phases, because they are not good or bad, they are just different." At the same time, she criticises the fact that this knowledge is still underestimated.
What means extra planning work for coaches and trainers can have many positive effects in the long term. "We will have more female athletes with fewer injuries and stress fractures. The athletes would be healthier and able to play competitive sport for longer," says Shakalio. A goal that Lea Feder is also striving for. She wants to set an example with her more sustainable way of training: "Because at some point, things move on, and a healthy body is the basis for everything that comes next - even after sport."
At a glance: Cycle and training
- Cycle-based training adapts the training intensity to the monthly cycle.
- In the phase before ovulation (follicular phase), the performance and willingness of women appears to be higher.
- Muscle-building hormones are at their highest during the follicular phase, which is why strength training is more effective.
- The pill means that female athletes lack these anabolic hormones, which have a performance-enhancing effect.
- Taking the pill prevents a real cycle, which can lead to physical warning signals (e.g. amenorrhoea) not being recognised.
- Not having a period used to be considered a blessing among female athletes. The opposite is now the case.
- After ovulation (luteal phase), women have an increased resting energy expenditure.
